Urban stormwater is one of the major challenges facing growing cities. In Victoria’s Port Phillip Bay catchment, decades of urbanisation have increased runoff, sediment and nutrient loads entering waterways.
A recent PhD thesis from RMIT University, undertaken by Dr Shamima Moazzem, demonstrates how eWater Source™ and eWater MUSIC™ can be used together to understand these pressures and evaluate the effectiveness of nature-based stormwater treatment systems at both local and catchment scales.
The research was conducted with support from eWater Group, providing access to industry-standard modelling software and technical guidance throughout the project.
From rainfall to the Bay: A complex challenge
When rain falls over Melbourne, it doesn’t simply disappear into drains. It flows across roofs, roads and car parks, picking up sediment, nitrogen and phosphorus before entering local waterways.
For Port Phillip Bay, one of Victoria’s most important environmental, recreational and economic assets, managing stormwater quality has become increasingly complex.
Protecting downstream ecosystems requires a whole-of-catchment view, combined with robust tools that can test how different interventions perform over time.
The researcher
As part of her doctoral research at RMIT University, Dr Shamima Moazzem, investigated how urban growth and climate pressures influence stormwater quality and quantity across the Port Phillip Bay catchment, and how nature-based treatment systems can help mitigate those impacts.
The thesis, Modelling Nature-Based Treatment Systems to Improve Water Quality in the Port Phillip Bay Catchment, reflects RMIT’s focus on applied, industry-relevant research, equipping graduates with the skills and tools used by water professionals across Australia.
Working across multiple sub-catchments, Dr Moazzem demonstrated advanced capability in hydrological and water quality modelling, bridging academic research and real-world planning challenges.
Why eWater Source and MUSIC matter
To capture the full stormwater story, from source to sea, Dr Moazzem used both eWater Source™ and eWater MUSIC™, leveraging their complementary strengths.
As Australia’s National Hydrological Modelling Platform, eWater Source was used to model rainfall, runoff and pollutant generation across the Port Phillip Bay catchment. This enabled simulation of:
• catchment-scale hydrology
• downstream pollutant loads
• impacts of urbanisation and climate scenarios
eWater MUSIC, Australia’s leading stormwater quality modelling tool, was then applied to assess the performance of nature-based treatment systems, including:
• constructed wetlands
• vegetated swales
By testing different land-use and development scenarios, MUSIC provided insight into how treatment systems reduce sediment and nutrient loads before stormwater enters receiving waterways.
Together, Source and MUSIC created a complete, integrated modelling framework, linking catchment-scale pressures with on-ground treatment performance.
Key findings from the research
The thesis delivered several insights highly relevant to urban stormwater management in Australia.
Urbanisation increases stormwater pressures The modelling showed a clear relationship between increased impervious surfaces and higher stormwater runoff and pollutant loads, particularly for nutrients commonly associated with urban land use.
Nature-based treatment systems are effective when appropriately designed Constructed wetlands and other nature-based systems were shown to significantly improve stormwater quality when they are correctly sized, located and designed in response to catchment conditions.
Climate change intensifies existing challenges Future climate scenarios highlighted how changes in rainfall patterns and storm intensity can compound stormwater impacts, increasing pressure on downstream waterways such as Port Phillip Bay.
Design and configuration influence performance The research reinforced that factors such as treatment area, hydraulic retention time, vegetation and substrate selection play a critical role in determining pollutant removal performance.
Turning research into practical insight
A defining strength of this work is its relevance to real-world decision-making.
Because the research used industry-standard tools, the modelling framework and findings can be readily understood and applied by practitioners. The work supports:
• stormwater management strategies in urban growth areas
• evidence-based investment in nature-based infrastructure
• catchment-scale planning to protect downstream waterways
Supporting a national community of practice
eWater Group’s involvement in this research reflects a broader commitment to education, capability-building and knowledge sharing across the water sector.
Beyond software, eWater supports:
• training and learning resources for students and practitioners
• technical guidance and user support
• an active national community using Source and MUSIC in real-world applications
Through partnerships with universities like RMIT, eWater is helping to ensure research, policy and practice remain closely connected, and that emerging water professionals graduate ready to contribute from day one.
Why does this matter?
As cities grow and climate pressures intensify, protecting waterways like Port Phillip Bay will depend on:
• strong science
• practical tools
• collaboration between universities, industry and government
This case study shows how Australian research and Australian-built technology are working together to meet that challenge, and how the next generation of water experts is already helping shape more sustainable outcomes.
Address
Support and Training
